EFFICIENCY OF 3 DIFFERENT HEMODIALYSIS MEMBRANES FOR PLASMA PORPHYRINREMOVAL

To assess the capability of three different membranes to remove porphy rins, plasma and dialysate porphyrin levels were fluorometrically meas ured in 10 patients with end-stage renal failure who were on hemodialy sis. Three different hemodialysis membranes were used: cuprophan, poly acrylonitrile, and cellulose triacetate. Total plasma porphyrin concen trations decreased after dialysis, but to a lesser extent when using t he cuprophan membrane (19%) than with the polyacrylonitrile (26%) or c ellulose triacetate (30%) membranes (P < 0.01). However, since the fre e plasma porphyrin fraction remained unchanged, it can be assumed that the equilibrium between protein-bound and non-protein-bound (free) po rphyrins is displaced toward the latter fraction. Dialysate porphyrin levels were lower (P < 0.01) when using the cuprophan membrane (10.1 m u g/session) than when using polyacrylonitrile (17.8 mu g/session) and cellulose triacetate (21.9 mu g/session). Although most of the plasma porphyrins are protein bound, our results show that hemodialysis can remove significant amounts of non-protein-bound (free) porphyrins. The polyacrylonitrile and cellulose triacetate membranes had a greater ca pacity for porphyrin removal than cuprophan. Thus, two high-permeabili ty membranes (polyacrylonitrile and cellulose triacetate) should be us ed whenever a reduction of plasma porphyrin levels is desired. (C) 199 5 by the National Kidney Foundation, Inc.